After NASA canceled the first all-female spacewalk in history due to a lack of spacesuits small enough to fit the average woman, Clinton chimed in with her advice. "Make another suit," she tweeted on Tuesday (March 26).
Clinton has long advocated for gender equality and the empowerment of women, and she almost became the first female president of the United States, when she narrowly lost the 2016 election. So, it should come as no surprise that she's still advocating for equal treatment of women in her post-election life. But NASA won't be taking Clinton's advice to "make another suit" in order to hit this big milestone for women in space, because the situation is unfortunately not that simple.
Make another suit. https://t.co/mu9w13xsi0March 26, 2019
For one, building another spacesuit in orbit would take about 12 hours of crew labor, NASA spokesperson Stephanie Schierholz told Space.com. "Given the very busy operational schedule onboard the station this spring — the spacewalks as well as several resupply missions that will begin arriving in April — the teams made the decision to keep the schedule by swapping spacewalkers rather than reconfiguring a spacesuit," she said.
But why didn't NASA have two of the right-size suits available to begin with, knowing that two women would be taking a spacewalk together? If the agency had all the parts in space already, why didn't it plan to use them? While many have speculated that NASA failed to sufficiently plan for its own spacewalk, a point that remains debatable, it's important to note that NASA made the decision to substitute one of the female spacewalkers with one of her male counterparts after she herself made that request.
This decision was based on my recommendation. Leaders must make tough calls, and I am fortunate to work with a team who trusts my judgement. We must never accept a risk that can instead be mitigated. Safety of the crew and execution of the mission come first. https://t.co/VU9QNaHHlKMarch 27, 2019
When NASA astronaut Anne McClain was training for her spacewalks on Earth, she was able to perform all of her tasks in both the medium and large spacesuits. Meanwhile, NASA astronaut Christina Koch, who was originally supposed to be McClain's spacewalking partner this Friday, has always worn a medium, Schierholz said. Medium is the smallest suit that NASA offers, and it's usually the size that women wear during spacewalks. McClain just so happened to be in between sizes, and she felt she could wear either one.
To prepare three spacewalks (scheduled for March 22, March 29 and April 29), the Expedition 59 crew put together two suits, officially known as extravehicular mobility units (EMUs), to be worn by the pairs of spacewalkers. One is a size medium, and the other is a large.
McClain wore both sizes of suits not only during her training on Earth, but also on the space station for fit checks, tailoring them to account for the way her body had changed in microgravity. For example, earlier this month she reported that she had grown 2 inches (5 centimeters) in space. Astronauts often grow taller in space because their spines relax and elongate elongate when not exposed to Earth's gravitational pull.
After McClain finished her first spacewalk last week, she decided that she did not want to try wearing the large suit for her second spacewalk. Even though she fit the large while training on Earth and then grew even taller while in space, she felt that the larger suit would be less comfortable and more difficult to work in, thereby adding even more risk to an already-risky job, Schierholz said. Instead, McClain will be replaced by NASA astronaut Nick Hague, who wore the large suit during last week's spacewalk.
It's true that NASA's 40-year-old spacesuits were built to fit the "average" astronaut at the time — in other words, the average male astronaut, considering the lack of women who had traveled to space back then. NASA has also long been plagued by gender inequality, much like most institutions in this country. But the fact that McClain will not be joining Koch for the first all-female spacewalk has less to do with gender bias and more to do with an astronaut's personal preferences — a decision that NASA argues it could not have foreseen.
Today, Christina Koch and Anne McClain were scheduled to perform the first all-female spacewalk together on the ISS. NASA cancelled the plan last minute though, due to a lack of spacesuits of the right sizes, replacing Ms McClain with Nick Hague, in a move that has sparked controversy. After the event, a number of conspiracy theories have emerged surrounding the ISS Spacewalk mission.
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Eagled-eyed viewers watching the live stream noticed something bizarre floating around behind Mr Hague as he worked on the space station.
It was quickly shared online by popular conspiracy channel Secureteam10, where presenter Tyler Glockner wildly claimed he thought it could be a UFO.
He said: “This is yet another example of NASA cutting the live feed after a UFO was spotted while one of the astronauts is out doing their spacewalk.
“You’ll notice for the good portion of the video there is no UFO.
The strange object hurtled past the ISS (Image: YOUTUBE)
The astronaut was working on the ISS (Image: YOUTUBE)
This is yet another example of NASA cutting the live feed after a UFO was spotted
Tyler Glockner
“The UFO appears just above the Earth’s horizon line and I want you guys to notice that, up until the UFO appears, the video feed is pretty stable.
“I want you guys to watch here, right as the UFO appears you’ll notice the live feed get more and moe interference until they finally decide to cut it.”
He went on to reveal how the live feed was then cut, claiming the astronaut was not aware a UFO had come into shot.
He added: “Here’s the point the UFO actually comes into view and you’ll notice the interference ramping up.
“Then finally the feed cuts.
The camera panned roung behind the astronaut (Image: YOUTUBE)
A strange anomaly appeared in the background (Image: YOUTUBE)
“Oddly enough, it incidentally happens right as the UFO comes in to view.
“Either the astronaut doesn’t see it, or there is a delay in communication, so they just cut the feed.”
Bizarrely, this incident is not the first of its kind.
A similar incident occured during the Soyuz mission (Image: GETTY)
During a pass-by of Chicago, two bright objects were seen flying across the screen, which appeared to startle the flight controller back at Mission Control in Houston.
He said: “Atlantis is approaching sunrise as it passes the Great Lakes area.
“There’s a, there’s a view of Chicago and some, uh, ice crystals, or other items being illuminated by the rising sun.
“Atlantis now moving into the sunrise, in just about the next minute or so.
“As that occurs ice crystals that come off the shuttle becomes illuminated."
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The bizarre event left conspiracy theorists, including Jeff Challender, convinced NASA had just captured something they should not have.
During Amazon Prime’s “Secret Space”, he revealed his view on how the event went down.
He said in 2017: “Just as the shuttle was passing over Chicago, two unusual objects were seen flying below.
“The first object appeared smaller and further away, but the second was very bright and moved at speed.
“Mission Control tried to zoom in and follow its progress until it was out of sight.
Mission Control were also baffled by an anomaly (Image: AMAZON PRIME)
The ISS is a low-Earth orbit satellite (Image: GETTY)
“Or perhaps they realised that the video goes out to the public.”
Mr Challender then went on to reveal why he believed the anomalies were not ice crystals.
He added: “The anomalies are not ice crystals sparkling in the sun.
“The announcer even said the sun will rise in a few minutes, this proves the objects were self-luminous.
“Good one, ice in the rising sun when the sun hasn’t even risen yet.”
Physicists from MIT and elsewhere have performed the first run of a new experiment to detect axions—hypothetical particles that are predicted to be among the lightest particles in the universe. If they exist, axions would be virtually invisible, yet inescapable; they could make up nearly 85 percent of the mass of the universe, in the form of dark matter.
Axions are particularly unusual in that they are expected to modify the rules of electricity and magnetism at a minute level. In a paper published today in Physical Review Letters, the MIT-led team reports that in the first month of observations the experiment detected no sign of axions within the mass range of 0.31 to 8.3 nanoelectronvolts. This means that axions within this mass range, which is equivalent to about one-quintillionth the mass of a proton, either don't exist or they have an even smaller effect on electricity and magnetism than previously thought.
"This is the first time anyone has directly looked at this axion space," says Lindley Winslow, principal investigator of the experiment and the Jerrold R. Zacharias Career Development Assistant Professor of Physics at MIT. "We're excited that we can now say, 'We have a way to look here, and we know how to do better!'"
Winslow's MIT co-authors include lead author Jonathan Ouellet, Chiara Salemi, Zachary Bogorad, Janet Conrad, Joseph Formaggio, Joseph Minervini, Alexey Radovinsky, Jesse Thaler, and Daniel Winklehner, along with researchers from eight other institutions.
Magnetars and munchkins
While they are thought to be everywhere, axions are predicted to be virtually ghost-like, having only tiny interactions with anything else in the universe.
"As dark matter, they shouldn't affect your everyday life," Winslow says. "But they're thought to affect things on a cosmological level, like the expansion of the universe and the formation of galaxies we see in the night sky."
Because of their interaction with electromagnetism, axions are theorized to have a surprising behavior around magnetars—a type of neutron star that churns up a hugely powerful magnetic field. If axions are present, they can exploit the magnetar's magnetic field to convert themselves into radio waves, which can be detected with dedicated telescopes on Earth.
In 2016, a trio of MIT theorists drew up a thought experiment for detecting axions, inspired by the magnetar. The experiment was dubbed ABRACADABRA, for the A Broadband/Resonant Approach to Cosmic Axion Detection with an Amplifying B-field Ring Apparatus, and was conceived by Thaler, who is an associate professor of physics and a researcher in the Laboratory for Nuclear Science and the Center for Theoretical Physics, along with Benjamin Safdi, then an MIT Pappalardo Fellow, and former graduate student Yonatan Kahn.
The team proposed a design for a small, donut-shaped magnet kept in a refrigerator at temperatures just above absolute zero. Without axions, there should be no magnetic field in the center of the donut, or, as Winslow puts it, "where the munchkin should be." However, if axions exist, a detector should "see" a magnetic field in the middle of the donut
After the group published their theoretical design, Winslow, an experimentalist, set about finding ways to actually build the experiment.
"We wanted to look for a signal of an axion where, if we see it, it's really the axion," Winslow says. "That's what was elegant about this experiment. Technically, if you saw this magnetic field, it could only be the axion, because of the particular geometry they thought of."
In the sweet spot
It is a challenging experiment because the expected signal is less than 20 atto-Tesla. For reference, the Earth's magnetic field is 30 micro-Tesla and human brain waves are 1 pico-Tesla. In building the experiment, Winslow and her colleagues had to contend with two main design challenges, the first of which involved the refrigerator used to keep the entire experiment at ultracold temperatures. The refrigerator included a system of mechanical pumps whose activity could generate very slight vibrations that Winslow worried could mask an axion signal.
The second challenge had to do with noise in the environment, such as from nearby radio stations, electronics throughout the building turning on and off, and even LED lights on the computers and electronics, all of which could generate competing magnetic fields.
The team solved the first problem by hanging the entire contraption, using a thread as thin as dental floss. The second problem was solved by a combination of cold superconducting shielding and warm shielding around the outside of the experiment.
"We could then finally take data, and there was a sweet region in which we were above the vibrations of the fridge, and below the environmental noise probably coming from our neighbors, in which we could do the experiment."
The researchers first ran a series of tests to confirm the experiment was working and exhibiting magnetic fields accurately. The most important test was the injection of a magnetic field to simulate a fake axion, and to see that the experiment's detector produced the expected signal—indicating that if a real axion interacted with the experiment, it would be detected. At this point the experiment was ready to go.
"If you take the data and run it through an audio program, you can hear the sounds that the fridge makes," Winslow says. "We also see other noise going on and off, from someone next door doing something, and then that noise goes away. And when we look at this sweet spot, it holds together, we understand how the detector works, and it becomes quiet enough to hear the axions."
Seeing the swarm
In 2018, the team carried out ABRACADABRA's first run, continuously sampling between July and August. After analyzing the data from this period, they found no evidence of axions within the mass range of 0.31 to 8.3 nanoelectronvolts that change electricity and magnetism by more than one part in 10 billion.
The experiment is designed to detect axions of even smaller masses, down to about 1 femtoelectronvolts, as well as axions as large as 1 microelectronvolts.
The team will continue running the current experiment, which is about the size of a basketball, to look for even smaller and weaker axions. Meanwhile, Winslow is in the process of figuring out how to scale the experiment up, to the size of a compact car—dimensions that could enable detection of even weaker axions.
"There is a real possibility of a big discovery in the next stages of the experiment," Winslow says. "What motivates us is the possibility of seeing something which would change the field. It's high-risk, high-reward physics."
Rapid spread of disease is a hazard in our interconnected world. The chytrid fungus Batrachochytrium dendrobatidis was identified in amphibian populations about 20 years ago and has caused death and species extinction at a global scale. Scheele et al. found that the fungus has caused declines in amphibian populations everywhere except at its origin in Asia (see the Perspective by Greenberg and Palen). A majority of species and populations are still experiencing decline, but there is evidence of limited recovery in some species. The analysis also suggests some conditions that predict resilience.
Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth’s biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease.
Highly virulent wildlife diseases are contributing to Earth’s sixth mass extinction (1). One of these is chytridiomycosis, which has caused mass amphibian die-offs worldwide (2, 3). Chytridiomycosis is caused by two fungal species, Batrachochytrium dendrobatidis [discovered in 1998, (4)] and B. salamandrivorans [discovered in 2013, (5)]. Both Batrachochytrium species likely originated in Asia, and their recent spread has been facilitated by humans (5, 6). Twenty years after the discovery of chytridiomycosis, substantial research has yielded insights about its epidemiology (2, 3, 7, 8), yet major knowledge gaps remain. First, the global extent of species declines associated with chytridiomycosis is unknown [see (2, 9) for initial assessments]. Second, although some regional declines are well studied, global spatial and temporal patterns of chytridiomycosis impacts remain poorly quantified. Third, ecological and life history traits have been examined only for a portion of declined species (10, 11). Finally, after initial declines, it is unknown what proportion of declined species exhibit recovery, stabilize at lower abundance, or continue to decline. Here we present a global epidemiological analysis of the spatial and temporal extent of amphibian biodiversity loss caused by chytridiomycosis.
We conducted a comprehensive examination of evidence from multiple sources, including the International Union for Conservation of Nature (IUCN) Red List of Threatened Species (12), peer-reviewed literature, and consultation with amphibian experts worldwide (data S1). We classified declined species into five decline-severity categories corresponding to reductions in abundance. Species declines were attributed to chytridiomycosis on the basis of diagnosis of infection causing mortalities in the wild or, if this was unavailable, evidence consistent with key epidemiological characteristics of this disease. Most evidence is retrospective because many species declined before the discovery of chytridiomycosis (data S1).
We conservatively report that chytridiomycosis has contributed to the decline of at least 501 amphibian species (6.5% of described amphibian species; Figs. 1 and 2). This represents the greatest documented loss of biodiversity attributable to a pathogen and places B. dendrobatidis among the most destructive invasive species, comparable to rodents (threatening 420 species) and cats (Felis catus) (threatening 430 species) (13). Losses associated with chytridiomycosis are orders of magnitude greater than for other high-profile wildlife pathogens, such as white-nose syndrome (Pseudogymnoascus destructans) in bats (six species) (14) or West Nile virus (Flavivirus sp.) in birds (23 species) (15). Of the 501 declined amphibian species, 90 (18%) are confirmed or presumed extinct in the wild, with a further 124 (25%) experiencing a >90% reduction in abundance (Figs. 1 and 2). The declines of all species except one (Salamandra salamandra affected by B. salamandrivorans) were attributed to B. dendrobatidis.
Fig. 1Global distribution of chytridiomycosis-associated amphibian species declines.
Bar plots indicate the number (N) of declined species, grouped by continental area and classified by decline severity. Brazilian species are plotted separately from all other South American species (South America W); Mesoamerica includes Central America, Mexico, and the Caribbean Islands; and Oceania includes Australia and New Zealand. No declines have been reported in Asia. n, total number of declines by region. [Photo credits (clockwise from top left): Anaxyrus boreas, C. Brown, U.S. Geological Survey; Atelopus varius, B.G.; Salamandra salamandra, D. Descouens, Wikimedia Commons; Telmatobius sanborni, I.D.l.R; Cycloramphus boraceiensis, L.F.T.; Cardioglossa melanogaster, M.H.; and Pseudophryne corroboree, C. Doughty]
Fig. 2Taxonomic distribution of chytridiomycosis-associated amphibian declines.
Each bar represents one species, and color denotes the severity of its decline. Concentric circles indicate, from inner to outer, order (Caudata or Anura), family, and genus. Full names are given only for families and genera that include >5 and >2 species, respectively; details for all taxa are in table S4. Within each taxonomic level, sublevels are ordered alphabetically. Protruding bars indicate species for which there is evidence of recovery. [Photo credits (left to right): Telmatobius bolivianus, I.D.l.R.; Atelopus zeteki, B.G.; and Craugastor crassidigitus, B.G.]
Declines were proportional to taxonomic abundance, with anurans having 93% of severe declines (they comprise 89% of all amphibian species). Within anurans, there has been marked taxonomic clustering of declines, with 45% of severe declines and extinctions occurring in the Neotropical genera Atelopus, Craugastor, and Telmatobius (Fig. 2) (16). Chytridiomycosis is lethal to caecilians (17), but there have been no caecilian declines due to the disease, although data are limited. The capacity for B. dendrobatidis to cause major declines is attributable to its maintenance of high pathogenicity (2, 18), broad host range (8), high transmission rate within and among host species (2, 7), and persistence in reservoir host species and the environment (19). For many species, chytridiomycosis is the principal driver of decline, exemplified by precipitous mass mortalities in undisturbed environments (2). In other species, chytridiomycosis acts in concert with habitat loss, altered climatic conditions, and invasive species to exacerbate species declines (20).
Most amphibian declines have occurred in the tropics of Australia, Mesoamerica, and South America (Fig. 1), supporting the hypothesis that B. dendrobatidis spread from Asia into the New World (6). Asia, Africa, Europe, and North America have had notably low numbers of declines attributable to chytridiomycosis, despite widespread occurrence of B. dendrobatidis (8). Relative lack of documented declines could reflect less knowledge of amphibian populations in Asia and Africa (3, 21), early introduction and potential coevolution of amphibians and B. dendrobatidis in parts of Africa and the Americas [e.g., (22)], the comparatively recent emergence of B. dendrobatidis in Western and Northeast Africa (6), or unsuitable conditions for chytridiomycosis. It remains unknown whether chytridiomycosis contributed to widespread amphibian declines reported in North America and Europe in the 1950s to 1960s (3, 21, 22) or current enigmatic salamander declines in eastern North America. Although the number of new declines has now eased (Fig. 3), additional declines could occur if B. dendrobatidis or B. salamandrivorans are introduced into new areas, highly virulent lineages are introduced into areas that currently have less-virulent lineages (6), and/or environmental changes alter previously stable pathogen-host dynamics (3).
Fig. 3Timing of chytridiomycosis-associated amphibian declines.
(A) Declines by year. Bars indicate the number of declines in a given year, stacked by decline severity. For species for which the exact year of decline is uncertain, the figure shows the middle year of the interval of uncertainty, as stated by experts or inferred from available data. (B) Cumulative declines. Curves indicate the cumulative number of declines in each decline-severity category over time. In (A) and (B), the arrows mark the discovery of chytridiomycosis in 1998.
Chytridiomycosis-associated declines peaked globally in the 1980s, between one and two decades before the discovery of the disease (Fig. 3 and table S1), and coincident with anecdotal recognition of amphibian declines in the 1990s (23). A second, smaller peak occurred in the early 2000s, associated with an increase in declines in western South America (Fig. 3 and fig. S1). Regionally, temporal patterns of decline are variable (fig. S1). For example, in some areas of South America and Australia, declines commenced in the late 1970s (2, 24), whereas in other areas, declines started in the 2000s (25). B. dendrobatidis is associated with ongoing declines in 197 assessed species. Ongoing declines after a transition to enzootic disease dynamics (19) might be driven by a lack of effective host defenses, maintenance of high pathogenicity (18), and presence of B. dendrobatidis in amphibian and nonamphibian reservoirs (7, 19).
We examined host life history traits and environmental conditions to understand why some species declined more severely than others, using multinomial logistic regression and accounting for the degree of evidence that chytridiomycosis was implicated in each species’s decline (fig. S2 and table S2). Decline severity was greatest for larger-bodied species, those occurring in consistently wet regions, and those strongly associated with perennial aquatic habitats. These patterns are likely due to favorable environmental conditions for B. dendrobatidis in wet regions (7), because the fungus dies when desiccated, as well as the general pattern of increased time to maturity in large-bodied amphibians resulting in less reproductive potential to offset mortality due to chytridiomycosis (26). Declines were less severe for species with large geographic and elevational ranges (Fig. 4), potentially owing to the greater chance of their range encompassing environmental conditions unfavorable for B. dendrobatidis (3) and/or information bias, because population extinctions can be assessed with more certainty in restricted-range species. Our results are consistent with previous studies that show that the risk of chytridiomycosis is associated with host aquatic habitat use, large body size, and narrow elevational range (10, 11).
Fig. 4Severity of chytridiomycosis-associated amphibian declines in relation to the geographic and elevational ranges of species.
(A) Declines in relation to geographic range. Each dot indicates a species, located randomly along the perimeter of a circle with radius equal to the log10 of the species’s geographic range in kilometers squared. (B) Declines in relation to elevational range. Horizontal bars, boxes, and vertical bars indicate, respectively, mean, first and second quartiles, and 95% quantiles of elevation ranges within each category of decline severity.
Encouragingly, of the 292 surviving species for which population trends are known, 60 (20%) have shown initial signs of recovery. However, recoveries generally represent small increases in abundance of individual populations, not complete recovery at the species level. Logistic regression showed the probability of recovery was lower for species that experienced more recent or more severe declines, for large-bodied or nocturnal species, and for species occurring at higher elevations (fig. S2 and table S3). When holding those predictors of recovery at their mean value, the chance of a species recovering from a severe (>90%) decline was less than 1 in 10. Low probability of recovery for high-elevation species might be related to suitable climatic conditions for fungal persistence as well as limited connectivity to source populations and/or longer host generation time (26). Some recoveries may be underpinned by selection for increased host resistance (18), whereas management of concurrent threats may have facilitated other recoveries (a promising avenue for conservation interventions) (27). Unfortunately, the remaining 232 species have shown no signs of recovery.
The unprecedented lethality of a single disease affecting an entire vertebrate class highlights the threat from the spread of pathogens in a globalized world. Global trade has recreated a functional Pangaea for infectious diseases in wildlife, with far-reaching impacts on biodiversity (this study), livestock (28), and human health (29). Effective biosecurity and an immediate reduction in wildlife trade are urgently needed to reduce the risk of pathogen spread. As mitigation of chytridiomycosis in nature remains unproven (30), new research and intensive monitoring that utilizes emerging technologies are needed to identify mechanisms of species recovery and develop new mitigation actions for declining species.
I. Dohoo, S. Martin, H. Stryhn, Veterinary Epidemiologic Research (VER Inc., Charlottetown, Canada, ed. 2, 2009).
M. Plummer, in Proceedings of the 3rd International Workshop on Distributed Statistical Computing (DSC 2003), K. Hornik, F. Leisch, Eds. (Vienna, Austria, 2003).
S. N. Stuart, M. Hoffmann, J. S. Chanson, N. A. Cox, R. J. Berridge, P. Ramani, B. E. Young, Threatened Amphibians of the World (Lynx Edicions, Barcelona, Spain; IUCN, Gland, Switzerland; Conservation International, Arlington, VA, 2008).
Acknowledgments: We thank M. Arellano, E. Courtois, A. Cunningham, K. Murray, S. Ron, R. Puschendorf, J. Rowley, and V. Vredenburg for discussions on amphibian declines. Comments from two anonymous reviewers greatly improved the manuscript. Funding: B.C.S. and D.B.L. were supported by the Australian National Environmental Science Program. L.B., L.F.S., T.A.K., and B.C.S. were supported by the Australian Research Council (grants FT100100375, LP110200240, and DP120100811), the NSW Office of Environment and Heritage, and the Taronga Conservation Science Initiative. S.C., W.B., A.M., and F.P. were supported by Research Foundation Flanders grants FWO3E001916 and FWO11ZK916N‐11ZK918N and Ghent University grant BOF16/GOA/024. S.C. was supported by Research Foundation Flanders grant FWO16/PDO/019. A.A.A. was supported by the Conservation Leadership Program (0621310), Vicerrectoría de Investigaciones, Universidad de Pamplona-Colombia, and Colciencias (1121-659-44242). T.C. was supported by the Coordination for the Improvement of Higher Education Personnel. A.C. was supported by the Amazon Conservation Association, the Amphibian Specialist Group, the Disney Worldwide Conservation Fund, the Eppley Foundation, the Mohammed bin Zayed Species Conservation Fund, the NSF, the Rufford Small Grants Foundation, and the Swiss National Foundation. I.D.l.R. was supported by the Spanish Government (CGL2014-56160-P). M.C.F. was supported by the NERC (NE/K014455/1), the Leverhulme Trust (RPG-2014-273), and the Morris Animal Foundation (D16ZO-022). S.V.F. was supported by the USFWS Wildlife without Borders (96200-0-G228), the AZA–Conservation Endowment Fund (08-836), and the Conservation International Critically Endangered Species Fund. P.F.Á. was supported by a Postdoctoral Research fellowship from the Mexican Research Council (CONACYT, 171465). T.W.J.G. was supported by the NERC (NE/N009967/1 and NE/K012509/1). J.M.G. was supported by the Universidad San Francisco de Quito (collaboration grants 11164 and 5447). M.H. was supported by scholarships from the Elsa-Neumann-Foundation and the German Academic Exchange Service (DAAD). C.A.M. was supported by the Atkinson Center for a Sustainable Future and the Cornell Center for Vertebrate Genomics. G.P.-O. was supported by DGAPA-UNAM and CONACYT while on sabbatical at the University of Otago, New Zealand. C.L.R.-Z. was supported by the NSF (1660311). S.M.R. was supported by a CONACYT Problemas Nacionales grant (PDCPN 2015-721) and a UC Mexus-Conacy cooperative grant. C.S.-A. was supported by the Chilean National Science and Technology Fund (Fondecyt no. 1181758). L.F.T. was supported by the São Paulo Research Foundation (FAPESP 2016/25358-3) and the National Council for Scientific and Technological Development (CNPq 300896/2016-6). J.V. was supported by the NSF (DEB-1551488 and IOS-1603808). C.W. was supported by the South African National Research Foundation. Author contributions: B.C.S., F.P., L.B., L.F.S., A.M., and S.C. conceived the research. B.C.S. collated the data and coordinated data collection. All authors contributed ideas and data. S.C. conducted the analysis, with input from B.C.S., F.P., A.M., C.N.F., and W.B. B.C.S., F.P., L.B., L.F.S., A.M., C.N.F., and S.C. wrote the paper with input from all authors. Competing interests: The authors declare no competing interests. Data and materials availability: All data are available in the manuscript or the supplementary materials.
This Hubble Space Telescope image reveals the gradual self-destruction of an asteroid, whose ejected dusty material has formed two long, thin, comet-like tails. The longer tail stretches more than 500,000 miles (800,000 kilometers) and is roughly 3,000 miles (4,800 kilometers) wide. The shorter tail is about a quarter as long. The streamers will eventually disperse into space. Credit: NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), and O. Hainaut (European Southern Observatory)
A small asteroid has been caught in the process of spinning so fast it's throwing off material, according to new data from NASA's Hubble Space Telescope and other observatories.
Images from Hubble show two narrow, comet-like tails of dusty debris streaming from the asteroid (6478) Gault. Each tail represents an episode in which the asteroid gently shed its material—key evidence that Gault is beginning to come apart.
Discovered in 1988, the 2.5-mile-wide (4-kilometer-wide) asteroid has been observed repeatedly, but the debris tails are the first evidence of disintegration. Gault is located 214 million miles (344 million kilometers) from the Sun. Of the roughly 800,000 known asteroids between Mars and Jupiter, astronomers estimate that this type of event in the asteroid belt is rare, occurring roughly once a year.
Watching an asteroid become unglued gives astronomers the opportunity to study the makeup of these space rocks without sending a spacecraft to sample them.
"We didn't have to go to Gault," explained Olivier Hainaut of the European Southern Observatory in Germany, a member of the Gault observing team. "We just had to look at the image of the streamers, and we can see all of the dust grains well-sorted by size. All the large grains (about the size of sand particles) are close to the object and the smallest grains (about the size of flour grains) are the farthest away because they are being pushed fastest by pressure from sunlight."
Gault is only the second asteroid whose disintegration has been strongly linked to a process known as a YORP effect. (YORP stands for "Yarkovsky-O'Keefe-Radzievskii-Paddack," the names of four scientists who contributed to the concept.) When sunlight heats an asteroid, infrared radiation escaping from its warmed surface carries off angular momentum as well as heat. This process creates a tiny torque that can cause the asteroid to continually spin faster. When the resulting centrifugal force starts to overcome gravity, the asteroid's surface becomes unstable, and landslides may send dust and rubble drifting into space at a couple miles per hour, or the speed of a strolling human. The researchers estimate that Gault could have been slowly spinning up for more than 100 million years.
Piecing together Gault's recent activity is an astronomical forensics investigation involving telescopes and astronomers around the world. All-sky surveys, ground-based telescopes, and space-based facilities like the Hubble Space Telescope pooled their efforts to make this discovery possible.
The initial clue was the fortuitous detection of the first debris tail, observed on Jan. 5, 2019, by the NASA-funded Asteroid Terrestrial-Impact Last Alert System (ATLAS) telescope in Hawaii. The tail also turned up in archival data from December 2018 from ATLAS and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) telescopes in Hawaii. In mid-January, a second shorter tail was spied by the Canada-France-Hawaii Telescope in Hawaii and the Isaac Newton Telescope in Spain, as well as by other observers. An analysis of both tails suggests the two dust events occurred around Oct. 28 and Dec. 30, 2018.
Follow-up observations with the William Herschel Telescope and ESA's (European Space Agency) Optical Ground Station in La Palma and Tenerife, Spain, and the Himalayan Chandra Telescope in India measured a two-hour rotation period for the object, close to the critical speed at which a loose "rubble-pile" asteroid begins to break up.
The asteroid 6478 Gault is seen with the NASA/ESA Hubble Space Telescope, showing two narrow, comet-like tails of debris that tell us that the asteroid is slowly undergoing self-destruction. The bright streaks surrounding the asteroid are background stars. The Gault asteroid is located 214 million miles from the Sun, between the orbits of Mars and Jupiter. Credit: NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), O. Hainaut (European Southern Observatory)
"Gault is the best 'smoking gun' example of a fast rotator right at the two-hour limit," said team member Jan Kleyna of the University of Hawaii in Honolulu.
An analysis of the asteroid's surrounding environment by Hubble revealed no signs of more widely distributed debris, which rules out the possibility of a collision with another asteroid causing the outbursts.
The asteroid's narrow streamers suggest that the dust was released in short bursts, lasting anywhere from a few hours to a few days. These sudden events puffed away enough debris to make a "dirt ball" approximately 500 feet (150 meters) across if compacted together. The tails will begin fading away in a few months as the dust disperses into interplanetary space.
Based on observations by the Canada-France-Hawaii Telescope, the astronomers estimate that the longer tail stretches over half a million miles (800,000 kilometers) and is roughly 3,000 miles (4,800 kilometers) wide. The shorter tail is about a quarter as long.
Only a couple of dozen active asteroids have been found so far. Astronomers may now have the capability to detect many more of them because of the enhanced survey capabilities of observatories such as Pan-STARRS and ATLAS, which scan the entire sky. "Asteroids such as Gault cannot escape detection anymore," Hainaut said. "That means that all these asteroids that start misbehaving get caught."
The researchers hope to monitor Gault for more dust events.
Thanks to an impressive collaboration bringing together data from ground-based telescopes, all-sky surveys and space-based facilities — including the NASA/ESA Hubble Space Telescope — a rare self-destructing asteroid called 6478 Gault has been observed.
Clear images from the NASA/ESA Hubble Space Telescope have provided researchers with new insight into asteroid Gault’s unusual past. The object is 4–9 kilometres wide and has two narrow, comet-like tails of debris that tell us that the asteroid is slowly undergoing self-destruction. Each tail is evidence of an active event that released material into space.
Gault was discovered in 1988. However, this observation of two debris tails is the first indication of the asteroid’s instability. This asteroid one of only a handful to be caught disintegrating by a process known as a YORP torque. When sunlight heats an asteroid, the infrared radiation that escapes from its warmed surface carries off both heat and momentum. This creates a small force that can cause the asteroid to spin faster. If this centrifugal force eventually overcomes gravity, the asteroid becomes unstable. Landslides on the object can release rubble and dust into space, leaving behind a tail of debris, as seen here with asteroid Gault.
“This self-destruction event is rare”, explained Olivier Hainaut (European Southern Observatory, Germany). “Active and unstable asteroids such as Gault are only now being detected by means of new survey telescopes that scan the entire sky, which means asteroids such as Gault that are misbehaving cannot escape detection any more.”
Astronomers estimate that among the 800,000 known asteroids that occupy the Asteroid Belt between Mars and Jupiter, YORP disruptions occur roughly once per year. The direct observation of this activity by the Hubble Space Telescope has provided astronomers with a special opportunity to study the composition of asteroids. By researching the material that this unstable asteroid releases into space, astronomers can get a glimpse into the history of planet formation in the early ages of the Solar System.
Understanding the nature of this active and self-destructive object has been a collaborative effort involving researchers and facilities around the world. The asteroid’s debris tail was first detected by the University of Hawaiʻi/NASA ATLAS (Asteroid Terrestrial-Impact Last Alert System) telescopes in the Hawaiian Islands on 5 January 2019. Upon review of archival data from ATLAS and UH/NASA Pan-STARRS (Panoramic Survey Telescope and Rapid Response System), it was found that the object’s larger tail of debris had been observed earlier in December 2018. Shortly thereafter, in January 2019, a second, shorter tail was seen by various telescopes, including the Isaac Newton, William Herschel, and ESA OGS Telescopes in La Palma and Tenerife, Spain; the Himalayan Chandra Telescope in India; and the CFHT in Hawaiʻi. Subsequent analysis of these observations suggested that the two events that produced these debris trails occurred around 28 October and 30 December 2018, respectively. These tails will only be visible for only a few months, after which the dust will have dispersed into interplanetary space.
Follow-up observations were then made by various ground-based telescopes. These data were used to deduce a two-hour rotation period for Gault, which is very close to the critical speed at which material will begin to tumble and slide across the asteroid’s surface before drifting off into space.
“Gault is the best ‘smoking-gun’ example of a fast rotator right at the two-hour limit”, explained lead author Jan Kleyna (University of Hawaiʻi, USA). “It could have been on the brink of instability for 10 million years. Even a tiny disturbance, like a small impact from a pebble, might have triggered the recent outbursts.”
Hubble’s sharp imaging provided valuable detail regarding the asteroid’s activity. From the narrow width of the streaming tails, researchers inferred that the release of material took place in short episodes lasting from a few hours to a couple of days. From the absence of excess dust in the immediate vicinity of the asteroid, they concluded that the asteroid’s activity was not caused by a collision with another massive object. Researchers hope that further observations will provide even more insight into this rare and curious object.
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
The research team’s work is presented in the scientific paper “The Sporadic Activity of (6478) Gault: A YORP driven event?”, which will be published in The Astrophysical Journal Letters.
ATLAS (Asteroid Terrestrial-impact Last Alert System) is an asteroid impact early warning system being developed by the University of Hawai’i and funded by NASA. It consists of two telescopes, 100 miles apart, which automatically scan the whole sky several times every night looking for moving objects.
The international team of astronomers in this study consists of Jan T. Kleyna (University of Hawai’i Institute for Astronomy, USA), Olivier R. Hainaut(European Southern Observatory, Germany), Karen J. Meech (University of Hawai’i Institute for Astronomy, USA), Henry H. Hsieh (Planetary Science Institute, USA, & Academia Sinica Institute of Astronomy and Astrophysics, Taiwan), Alan Fitzsimmons (Queen’s University Belfast Astrophysics Research Centre, UK), Marco Micheli (European Space Agency Near Earth Object Coordination Centre, Italy, & National Institute for Astrophysics - Osservatorio Astronomico di Roma, Italy), Jacqueline V. Keane (University of Hawai’i Institute for Astronomy, USA), Larry Denneau (University of Hawai’i Institute for Astronomy, USA), John Tonry (University of Hawai’i Institute for Astronomy, USA), Aren Heinze (University of Hawai’i Institute for Astronomy, USA), Bhuwan C. Bhatt(Indian Institute for Astrophysics, India), Devendra K. Sahu (Indian Institute for Astrophysics, India),
Detlef Koschny (European Space Agency European Space Research and Technology Centre, the Netherlands & Near Earth Object Coordination Centre, Italy, & Technical University of Munich, Germany), Ken W. Smith (Queen’s University Belfast Astrophysics Research Centre, UK), Harald Ebeling (University of Hawai’i Institute for Astronomy, USA), Robert Weryk (University of Hawai’i Institute for Astronomy, USA), Heather Flewelling (University of Hawai’i Institute for Astronomy, USA), and Richard J. Wainscoat (University of Hawai’i Institute for Astronomy, USA).
Image credit: NASA, ESA, NASA, ESA, K. Meech and J. Kleyna (University of Hawaii), O. Hainaut (European Southern Observatory), L. Calçada
Links
Contacts
Jan Kleyna Institute for Astronomy Honolulu, HI, USA Tel: +1 808 956-0797 Email: kleyna@hawaii.edu
Olivier Hainaut European Southern Observatory Garching bei München, Germany Tel: +49 89 3200 6752 Email: ohainaut@eso.org
Dr. Karen Meech Institute for Astronomy Honolulu, HI, USA Tel: +1-808-956-6828 Email: meech@ifa.hawaii.edu
Bethany Downer ESA/Hubble, Public Information Officer Garching bei München, Germany Email: bethany.downer@partner.eso.org
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